The long term objective is to develop a noninvasive hyperacute diagnostic reagent for acute myocardial infarct detection and visualization. It should be a low-tech, technetium-99m based reagent which can be used with simple gamma cameras which are already available in almost all hospitals in the US. It should be sensitive and be able to demarcate infarcted myocardium very early after the on-set of chest pain (i.e. within 1 to 3 hours) which should enable monitoring of the efficacy of thrombolytic intervention. Tc-99m labeled glucaric acid is such a reagent which localizes very quickly in experimental myocardial infarction. It is a radiolabeled natural metabolite which exist as the major organic acid in the urine and is also found in the blood in man. It is non-toxic and nonimmunogenic but being similar to glucose, may utilize the same glucose transport system. However, glucaric acid possessing 2 carboxylic acid residues, should not be able to freely diffuse across cell membranes. The mechanism of localization and targeting intracellularly will be investigated. At present, the number of equivocal diagnosis for acute myocardial infarction is about one-third of 1.5 million new infarcts annually. The establishment of such a reagent for hyperacute diagnosis of myocardial infarction should facilitate a more accurate diagnosis and thereby conserve scarce health care resources. Is should reduce or eliminate inappropriate hospitalization by providing very fast rule-out or confirmatory diagnosis. PROPOSED COMMERCIAL APPLICATION: The availability of a hyperacute diagnostic reagent for myocardial infarction, which is low-cost, low- tech/high diagnostic accuracy should provide a very user-friendly approach with very high clinical benefit. It should promote its utilization not only in assessment of thrombolytic therapy, but also find use in the exclusion of myocardial infarction in patients with equivocal presentation.